Dec. 27: Randi Zuckerberg, the sister of Facebook chief executive Mark, has complained after a "private" photo she posted on the social network was spread on Twitter by someone she had not intended to see it.
Randi Zuckerberg, who worked for Facebook until last year, was apparently caught out by tagging other family members in the photograph, which meant their friends, as well as hers, could see it.
The picture, which shows the Zuckerberg family in their kitchen, reacting to Facebook's new iPhone "Poke" app, appeared in the newsfeed of Callie Schweitzer, a friend of another sister.
She reposted it to Twitter, where it was widely shared, which Zuckerberg complained was "way uncool".
"Not sure where you got this photo. I posted it to friends only on Facebook," she told Schweitzer.
Schweitzer explained that she had seen it in her Facebook feed because she is friends with another member of the Zuckerberg family, tagged in the picture. Randi Zuckerberg accepted the explanation but said her annoyance was "not about privacy settings, it's about human decency".
"I'm just sensitive to private photos becoming 'news'," she added.
The incident nevertheless drew schadenfreude from Facebook critics, who have long claimed it makes members share more than they intend to and that privacy settings are too complicated.
Dan Lyons, a technology commentator at ReadWrite, said Zuckerberg's "human decency" claim had taken her anger to a "whole new level of mental".
"How... invasive. What a violation. How terrible that someone might take something that belongs to you and use it in ways that you had not anticipated, and for which you had not given explicit permission!," he said sarcastically, after listing a series of alleged moral and privacy failing by Facebook.
Most recently, Facebook's prompted an outcry by members of its smartphone photo service Instagram by changing the terms and conditions to give it much greater power over the images they post. The anger forced a partial climbdown.
Danny Sullivan, of Search Engine Land, rejected Randi Zuckerberg's claim it was "not about privacy settings".
"Actually, it's a lot about privacy settings, and even Facebook's improved systems makes this hard," he said.
It is not the first time the Zuckerberg family has been unwillingly exposed by Facebook. Last December, a security flaw meant strangers were able to access some of Mark Zuckerberg's private images, which were then widely published online.
"Digital etiquette: always ask permission before posting a friend's photo publicly. It's not about privacy settings, it's about human decency," she posted on Twitter.
"The thing that bugged me about Randi Zuckerberg's response is that she used her name as a bludgeoning device. Not everyone has that. She used her position to get it taken it down," said Eva Galperin of the Electronic Frontier Foundation, a privacy advocacy group in San Francisco.
While Facebook has made improvements in explaining the social network's privacy settings, Galperin said they remain confusing to most people. She added that with people using Facebook as part of their everyday lives, the consequences of fumbling privacy settings can become serious.
"Even Randi Zuckerberg can get it wrong. That's an illustration of how confusing they can be," she said.
The Menlo Park, California, company recently announced it is changing its privacy settings with the aim of making it easier for users to navigate them. The fine-tuning will include several revisions that will start rolling out to Facebook's more than 1 billion users during the next few weeks and continue into early next year.
The most visible change ' and perhaps the most appreciated ' will be a new "privacy shortcuts" section that appears as a tiny lock at the top right of people's news feeds. This feature offers a drop-down box where users can get answers to common questions such as "Who can see my stuff?"
But Galperin said Wednesday's incident also illustrates a general concern about Internet privacy. Essentially, she said, if you share information or a photo with your social network, people in your network have the ability to share that with whomever else they choose.
The mobile photo-sharing service Instagram, which is owned by Facebook Inc., had to answer to backlash to privacy concerns recently when new terms of service suggested user photos could be used in advertisements. The company later said it would remove the questionable language.
Twitter user @cshweitz shared a photo of the Zuckerberg family checking out Poke, the latest mobile app developed by Facebook, early Wednesday.
The picture had originally been posted on Facebook by Randi Zuckerberg, who expressed her displeasure with the photo being shared publicly on Twitter.
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"Not sure where you got this photo. I posted it to friends only on FB. You reposting it to Twitter is way uncool," Zuckerberg tweeted to @cshweitz, according to a screenshot of the tweet grabbed by BuzzFeed.
The Twitter user, Callie Schweitzer, apologized, explaining that she follows Randi Zuckerberg on Facebook and saw the picture at the top of her News Feed.
Randi Zuckerberg said she accepted the apology a few minutes later and explained that Schweitzer probably saw the picture because Schweitzer is Facebook friends with Randi Zuckerberg's sister, who was tagged in the photo.
Photos that have been tagged are visible to friends of every user in the photo, not just the friends of the user who posted it. It is one of the loopholes in the social network's privacy feature that some users say should be plugged.
Many of the tweets by both users, including the one with the photo, have since been deleted.
"Digital etiquette: always ask permission before posting a friend's photo publicly. It's not about privacy settings, it's about human decency," Randi Zuckerberg tweeted after the photo was removed.
The incident has turned out to be somewhat of an embarrassment for Facebook.
Users frequently complain about the social network's confusing privacy settings, and with Randi Zuckerberg falling victim to them, some users haven't been shy about voicing their complaints.
"This is absolutely about privacy settings. That person shouldn't have seen it. Your brother's site is doing this to us all!" a user responded to Randi Zuckerberg's tweet.